Method and apparatus for felling trees

ABSTRACT

A mobile tree feller skidder including a felling head attached to the free end of an extendible and retractable boom pivotally mounted on a mobile vehicle to slew about a vertical axis. The felling head includes a grapple accumulator and shear mounted on a common frame, the grapple accumulator having resilient means biasing the bite to a selected minimum size and a gate through which trees are forced sideways into the accumulator against the spring bias by forcing the felling head onto a standing tree of the shear jaw in an open position. A tree or trees are first placed in the accumulator and then severed and the felling head moved to place a further tree in the accumulator with the process continuing until a desired number of trees are collected in the accumulator and then felled, depositing the butt end of the collected trees on a tong-type bunk, mounted on the vehicle.

United States Patent 1 Hamilton l l METHOD AND APPARATUS FOR FELLINGTREES [75] Inventor: Douglas l Hamilton,

Mount Royal, Canada [22] Filed: Mar. 2, 1971 [21] Appl. No.: 120,300

[30] Foreign Application Priority Data Mar. 3, 1970 Canada 076349 52 Us.01. 144/309 AC, 144/3 D, 144 34 R 51 rm. c1 A0lg 23/08 [58] Field ofSearch 144/3 1), 34 E, 309 AC [56] References Cited UNITED STATESPATENTS Larson et al 144/3 D 1/1970 Larson et al 144/3 D 3/1968 Larsonet al 144/3 D Primary Examiner-Gerald A. Dost Attorney-Jacobi, Lilling &Siegel [5 7] ABSTRACT A mobile tree feller skidder including a fellinghead attached to the free end of an extendible and retractable boompivotally mounted on a mobile vehicle to slew about a vertical axis. Thefelling head includes a grapple accumulator and shear mounted on acommon frame, the grapple accumulator having resilient means biasing thebite to a selected minimum size and a gate through which trees areforced sideways into the accumulator against the spring bias by forcingthe felling head onto a standing tree of the shear jaw in an openposition. A tree or trees are first placed in the accumulator and thensevered and the felling head moved to place a further tree in theaccumulator with the process continuing until a desired number of treesare collected in the accumulator and then felled, depositing the buttend of the collected trees on a tong-type bunk, mounted on the vehicle.

22 Claims, 8 Drawing Figures Patented July 31, 1973 5 Sheets-Sheet 1 w/was ATTORNEYS hunted July 31, 1973 3,749,143

5 Sheets-Sheet 2 Patented July 31, 1973 3,749,143

5 Sheets-Sheet 5 Patwted July 31, 1?3 3,749,143

5 Sheets-Sheet 4 Pmnud Jul 31, 1973 5 Sheets-Sheet 5 I METHOD ANDAPPARATUS FOR FELLING TREES The present invention relates toimprovements in the method and apparatus in the art of tree felling.

Prior apparatus for felling trees includes felling heads mounted onanextendible and retractable boom, each tree being handled individually.The cycle for handling each tree consists of manipulating the boom toplace the grapple portion of the felling head on the base of the treeand grasp the same after which the serving device severs the tree closeto the ground. The tree is then controllably felled by the felling headand placed upon the ground or, alternatively, on a bunk-type skidder onwhich the boom is also mounted and the cycle is repeated to harvest thenext tree.

Attempts have been made to sever a cluster of trees by clamping the sametogether and severing the same at one time as exemplified by Larsons US.Pat. No. 3,238,981 issued Mar. 8, 1966. This process, however, islimited to the number of trees that are sufficiently close to oneanother in order to be grasped by the gasping apparatus.

More recent developments include severing standing trees and collectingthe severed trees in an accumulator which retains the same adjacent thesevering device such that several trees may be severed and subsequentlyfelled. One such apparatus is disclosed in Larson et al. Canadian Pat.No. 815,870 issued June 24, 1969. In the patented structure, there isdisclosed an accumulator mounted on the end of an extendible andretractable boom for collecting trees after they have been'severed by ashear mechanism located adjacent the accumulator. The trees are severedby the severing device and subsequently positioned in the accumulatorwhere they are retained in an upright position while furthertrees'are'successively severed and placed in the accumulator.

A principal object of the present invention is to improve the efficiencyof harvesting standing trees and this is accomplished in the presentinvention by positioning the standing tree to be servered in theaccumulator and subsequently severing the same. This eliminates thetransfer step necessary in the Larson et al apparatus where, asmentioned, the tree is severed and then moved from the severingapparatus into the accumulator.

The applicant, in developing the present invention, has kept thefollowing objectives in mind:

I. to provide an accumulator-type grapple for use in handling trees soas to reduce the swing, unloading cycles;

2. keep the grapple simple and as light as possible for purposes ofstability;

3. keep the grapple as compact as possible for the purpose ofmanoeuverability of the felling head on selection cutting and/or movingthe felling head during loading and unloading operations where theaccumulator-type grapple, in accordance with the present invention, ismounted on a frame with a shear for severing standing trees. Compactnessin this regard is obtained by having the accumulator located directlyover the shear.

Accordingly, in accordance with one aspect of the present invention,there is provided a method in felling trees which comprises:

a. placing a growing tree or trees in an accumulator;

b. positively gripping said tree;

c. severing said tree; and

d. placing a further tree or trees in said accumulator and repeating thestep of severing the same until the accumulator has been filled with thedesired quantity of trees severed from their stump.

In accordance with a further aspect of the present invention, there isprovided apparatus for use in effecting the foregoing method, saidapparatus including a grapple characterized in combination of:

a. a frame having a jaw with a throat;

b. resilient means biasing said jaw to a selected minimum size andproviding a bite variable in size upon the application of forces appliedthereto; and

. a self-closing gate in said throat permitting entry of elongatedobjects therethrough into the bite by sideways movement of such objectand retain such object, along with further objects accumulated therein,in said grapple by the biasing force provided from the means resilientlybiasing the bite of the grapple to its minimum size.

In accordance with a still further aspect of the present invention,there is provided a felling head for use in felling standing trees whichincludes:

A. a grapple mounted on a frame and consisting of a free accumulator incombination with a gate allowing entry of trees into the accumulator andmeans for retaining the trees in the accumulator; and

B. a severing device secured to said frame characterized in that acutting member of severing device traverses an imaginary extension ofthe end area of the accumulator whereby standing trees are severedsubsequent to being placed in the accumulator.

The invention is illustrated by way of example in the accompanyingdrawings wherein:

FIG. I is an oblique diagrammatic illustration of the grapple of anaccumulator and severing device associ ated therewith mounted on thefree end of an extendible and retractable boom carried by a mobileskidder;

FIG. 2 is a side elevational view of the accumulator illustrated in FIG.1;

FIG. 3 is a top plan view of FIG. 2;

FIG. 4 is a view similar to FIG. I but including only the accumulatorand shear portion and illustrating a modified version of theaccumulator;

FIG. 5 is a side elevational view similar to FIG. 2, illustrating astill further modified accumulator;

FIG. 6 is a top plan view of FIG. 5;

FIG. 7 is a top plan view similar to FIG. 6, illustrating a stillfurther modified accumulator; and

FIG. 8 is a top plan view similar to FIGS. 6 and 7, illustrating a stillfurther modified accumulator.

Referring now in detail to the drawings, illustrated in FIG. 1 is a treefeller skidder 10 consisting of a mobile tractor 20 having a bunk 30attached thereto adjacent the trailing end thereof and anchoring thebutt end of trees T1, T2, T3 and T4 to the vehicle for skidding thesame. An extendible and retractable boom assembly 40 is pivotallymounted on the vehicle by a post 40A to slew about a vertical axis andcarried on the'free end of the boom is a felling head 50. The fellinghead consists of a shear 60 and a grapple accumulator with the shearbeing located vertically below the accumulator to sever growing treesplaced in the accumulator. The accumulator includes a gate biased to anormally closed position and controllably opened by the vehicle operatorsuch that trees accumulated in the accumulator may be deposited on thebunk when the accumulator is moved to a position vertically above thebunk on the vehicle. The felling head assembly 50 may be readilyattached to the free end of any extendible and retractable boom. ln thepresent embodiment, there is illustrated a telescopic boom as this isdeemed to more readily provide the function of pressing the accumulatoronto standing trees against a spring-biased treeengaging mechanism inthe accumulator which will be described more fully hereinafter. As willbe readily apparent from FIG. 1, the mobile feller is moved into thevicinity of standing trees and a tree in a growing position is placed inthe accumulator and thereafter severed vertically below the accumulatorsuch that the severed tree remains standing up in the accumulator withpreviously severed trees while the felling head is manipulated to aposition for grasping and felling a further tree.

The bunk 30 includes a plurality of arcuate arms controllably movable inpairs for selectively engaging and dis-engaging trees placed on theotherwise generally U-shaped bunk. The bunk is fully disclosed inapplicants U.S. Pat. No. 3,289,865 issued Dec. 6, 1966, and shouldfurther description of the same be desired, it may be obtained from suchpatent.

The boom 40 is a telescopic type having a fixed section 41 pivotallymounted on the post 40A by a pin 45 and is controllably moved by ahydraulic pistoncylinder assembly which is extendible and retractableand connected at opposed ends respectively to the boom section 41 andthe post 50. Telescopically arranged within fixed boom member 41 aremembers 42 and S3 controllably moved to extend and retract the boom byhydraulic cylinders, cables, or the like, cables being diagrammaticallyillustrated and wound on a driven winch assembly 44 located on the boomsection 41. There are numerous telescopic booms known which are readilysuitable for the present apparatus and, accordingly, no further detaileddescription of the same is believed necessary. The telescopic boom 40may even be replaced by a knuckle boom or the like, but as will be seenhereinafter and previously mentioned, the telescopic boom is deemed moresuitable.

The felling head is pivotally mounted on the free end of the telescopicboom 40 by a pin 51 and is controllably tilted by an extendible andretractable hydraulic piston-cylinder assembly 52 connected at opposedends respectively to the boom and felling head by pins 53 and 54.

The shear 60 consists of a pair of shear blades 61 and 62 pivotallyconnected to respective ones of a pair of lever arms 63 by a pin 64, thelever arms 63 being pivotally mounted on opposed ends of an elongatedframe 64 by respective ones of a pair of pivot pins 65. Movement of thecutting members toward and away from one another is effected byextension and retraction of an hydraulic piston-cylinder assembly 66controlled by the operator on the vehicle. The shear blades 61 and 62are further connected to the frame 64, for example, by slidingengagement as illustrated in Keslers Canadian Pat. No. 826,462 issuedNov. 4, l969 or some other sliding pivot or, alternatively, a pair oflink members each pivotally connected to the frame and pivotallyconnected in spaced relation thereto with respective ones of the shearblades or mountings therefor, as for example illustrated in applicant'sCanadian Pat. No. 791,445 issued Aug. 6, 1968. The shear blades 61 and62 have cutting edges in face-to-face relation movable in a directiontoward and away from one another traversing a projected bite area of thegrapple accumulator. As previously mentioned, trees accordingly arefirst placed in the accumulator and subsequently severed by the shear.As the trees accumulate, they are pressed rearwardly as will be seenhereinafter, in the accumulator against a spring bias and the shearblades accordingly need only traverse sufficient area to sever as manytrees as are placed in the accumulator at one time and which, undernormal circumstances, would be only one tree adjacent the gate 70.

The grapple accumulator 70 illustrated in FIGS. 1, 2 and 3 consists ofrespective upper and lower U-shaped members 71 and 72 rigidly connectedto a frame member 73 and projecting forwardly therefrom. The framemember 73 has an aperture 74 to receive pivot mounting pin 51 attachingthe felling head to the boom. The U-shaped members 71 and 72 aresimilarly oriented having respective throats 75 and 76 selectivelyopened and closed by a gate consisting respective members 77 and 78.Each gate member 77 and 78 includes a pair of segmental plate members 79connected to opposed ends of a shaft 80 pivotally mounted on the upperand lower plates 71 and 72. The gate members 77 and 78 are arranged toallow a tree or trees to be pressed therethrough into the bite of theU-shaped frame members 71 and 72 and the gate is biased to a normallyclosed position by an accumulator 81 connected to the respective pair ofrods 80 through a link system. Each rod 80 has a pair of lugs 82 securedthereto receiving a link member 83 therebetween and which is pivotallyattached thereto by pin 84. The opposite end of the links 83 areconnected to respective ones of a pair of intermediate shafts 85joumalled for rotation in the respective upper and lower members 71 and72. The link 83 as seen in FIG. 2, is connected by a pin 86 to a furtherlink 87 which, in turn, is pivotally connected to a lug secured to theshaft 85 by a pin 88. Link 87 is connected by a pin 90 to the hydrualicaccumulator 81. The accumulator 81 applies forces through the linkmembers 83 normally moving the gate portions 77 and 78 to a closedposition. If desired, accumulator 81 may be replaced by an extendibleand retractable hydrualic piston-cylinder assembly such that the gatemay be opened by external physical forces applied to the gate membersand selectively opened and closed by appropriate control of fluid to thecylinder.

Referring to FIG. 1, there are illustrated trees T5 and T6 held in theaccumulator with tree T7 located partially through the gate. The treesare placed in the accumulator before severing and the severed treesretained in the accumulator so as to be held in an upright position. Inorder to permit moving the felling head from one position to another,the trees are clampingly engaged in the accumulator and accordinglyreference throughout the specification has been made herein to a grappleaccumulator. The trees are held in the accumulator by resilient meanspressing the trees against the gate, such resilient means providing avariable sized bite which is increased in size by physically forcing atree or trees through the gate into the accumulator against such springbias. Various embodiments of the resilient means for applying forces tothe trees are illustrated with one such means in FIGS. 1 and 2consisting of respective upper and lower spring members 90 and 91secured to the frame adjacent respective U-shaped members 75 and 76 andhaving portions engageable with the tree engaged in the accumulator.

Referring to FIG. 3, spring assembly 90 consists of semi-ellipticalsprings 92 and 93 interconnected at opposed ends by respective shackles94 and 95. The spring 92 is secured to the grapple frame member 73 by aclamp 96 while spring member 93 is fastened to a plate 97 slidablymounted for movement in a guide channel formed in the U-shaped member 75associated therewith. The plate 97 has an arcuate edge 98 engageablewith the trees as they pass through the gate of the accumulator. Theplate 97 may be held for sliding movement in any convenient manner as,for example, channels or the like in the U-shaped frame or somemechanical equivalent of the same. The intended purpose of plate 97 isto provide an arcuate outer edge surface 98 which abutts the treesholding the same firm in the accumulator regardless of the number oftrees which might be collected therein within, of course, the capacityof the accumulator. Movement of the plate 97 varies the bite of theaccumulator and thereby varies the treeholding capacity of the same,resilient bias being provided by springs 92 and 93. The springcharacteristics of the same are chosen such as to provide the necessaryforce to hold the trees in an upright position during movement of thefelling head in collecting further trees in the same. The lower springunit 91 is the same as that described with reference to spring 90 andaccordingly, it will be seen the trees are engaged at two positionsspaced longitudinally therealong.

The spring assemblies 90 and 91 may be replaced by various equivalentsfor applying resilient forces against trees in the accumulator holdingthe same therein. A modified version of the same is illustrated in FIG.4 wherein a pair of semi-elliptical spring assemblies 100 areinterconnected by a bar member 101 midway between opposed ends ofrespective ones thereof with such oposed ends being anchored as, forexample, by passing through apertures in the upper and lower U- shapedmembers 71 and 72. In passing through the apertures, the ends of thesprings are slidably mounted in the respective U-shaped members avoidingthe use of shackles and bar 101 provides engagement with the trees to beretained in the accumulator pressing the same against the gate. Themember 101 may be a straight bar or arcuate in plan view, having asurface corresponding to surface 98 of the embodiment illustrated inFIG. 3. Also, in utilizing the bar 101, the engaging surface may besmooth, spiked, or ribbed depending upon the desired results required inholding the trees.

Before describing further various embodiments of the spring assembly forapplying resilient forces to the trees, it will be noted in FIG. 4 thereis illustrated a modified version of the gate-closing apparatus whereinaccumulator 81 has been replaced by a plurality oftorsion springs 120mounted on the gate mounting shafts 80 and anchored at opposed endsrespectively to the frame portion of the accumulator and the shaft.Resilient bias closing the gate accordingly is provided by the torsionsprings 120 and selective opening of the gate is accomplished by controlof a hydraulic piston-cylinder assembly 130 anchored at opposed endsrespectively to the accumulator frame and the gate portion associatedtherewith. In effect, a pair of hydraulic piston-cylinder assemblies 30are utilized, only one being illustrated in FIG. 4 connectedrespectively at opposed ends by pins I31 and 132 to the frame and a lugextension secured to and projecting from the shaft 80. A still furthermodification is illustrated in FIG. 4 wherein the hydraulicpiston-cylinder assembly 52, instead of being connected directly to thefelling head, has pivot pin 54 interconnecting a pair of link members 55and 56 anchored at their opposite end respectively to the boom andfelling head by pins 57 and 58.

Referring now to FIGS. 5 and 6, there is illustrated a modified springmeans consisting of a cable attached to the free end of a pair ofsemi-elliptical springs 141 (only one shown) anchored intermediateopposed ends thereof by brackets 142 to the accumulator frame. The cableattached to the pair of springs 141 forms a cradle for engaging trees inthe accumulator at vertically spaced positions designated respectively143 and 144 in FIG. 5. In the embodiment illustrated in FIGS. 5 and 6,the gate portions 77 and 78 are controlled respectively by accumulatorsand 151 which alternatively may be extendible and retractable hydraulicpiston-cylinder assemblies controlled by the operator of the vehicle forselectively opening the gate after trees have been accumulated in theaccumulator and which are to be depositied by dropping the same on thebunk of the vehicle or some other apparatus.

In FIG. 7, there is illustrated a still further resilient means varyingthe size of the bite of the grapple accumulator and which consists of acable anchored at opposed ends to respective ones of a pair of tensionspring members 181 which, in turn, are anchored to the grapple frame bya pin or the like 182. The cable is attached to the opposite end of thespring member 181 and passes over a pulley or sheave 183 mounted onrespective ones of the pair of shafts 80.

A still further embodiment of the grapple accumulator is illustrated inFIG. 8. In each of the foregoing embodiments, the upper and lowermembers 75 and 76 are rigid U-shaped members having a throat with entryof objects thereto being controlled by opening and closing of the gate.In FIG. 8, it will be noted the grapple accumulator is provided withrespective jaw members 201 and 202 pivotally mounted on the frame 73 byrespective pivot pins 203 and 204. The gate portions 77 and 78 arecarried by respective members 201 and 202 and accordingly, such gateneed only be a one-way control permitting only entry of trees into theaccumulator 70. Opening of the grapple jaw in such case may be effectedby pivoting the respective members 201 and 202 about pivot pins, forexample, by an extendible and retractable hydraulic piston-cylinderassembly 204 controlled by the operator and connected at opposed ends torespective members 201 and 202 by pins 205 and 206. The bite of the jawprovided by the grapple may be resiliently retained at a minimum size byapparatus of any of the foregoing types. for example a cable 180 andspring means 181 illustrated and described with reference to FIG. 7. Theaccumulator, accordingly, may have the bite size thereof varied by thecable member 180 and/or movement of the grapple jaw members 201 and 202.

From the foregoing, it will be readily apparent there are numerousmodifications to resilient means for retaining trees in the accumulatorafter they have been severed from their stump. The felling head, inaccordance with the present invention and various other aspects of thesame, all operate in the same manner by having trees pass through thegate while still attached to their stump and placed in the accumulatorbefore severing is effected. In each of the foregoing embodiments, thefelling head is placed on the tree by having the shear in ajaw openposition and pressing the felling against the tree by extension of theboom to force the tree through the gate against the spring-biased meansfor retaining the tree in the accumulator, the gate closing after thetree has passed therethrough holding the tree in the accumulator.Effectively, the felling head acts as a clinging member to the tree bythrowing the same. against the tree with force sufficient to cause thetree to pass through the gate and this is found to be accomplishedeffectively by a telescopic boom. As previously mentioned however, otherbooms may be used for the same purpose but maximum speed and efficiencyis found to be obtained using telescopic booms. After the operator hasextended the boom sufficiently to place a standing tree in theaccumulator, he controls operation of the shear mechanism, or this maybe done automatically upon closing of the gate, to sever the tree andthe cycle is then repeated by moving the felling head to a furtherstanding tree to be severed and placing the same in the accumulator byforcing the same onto the tree through extension of the boom. After asufficient number of trees have been collected in the accumulator, inkeeping with the capacity of the same, the boom and felling head aremanipulated placing the butt end of the collected trees on the bunk ofthe vehicle 20. lt can thus readily be seen applicant has providedimprovements in the harvesting of trees by minimizing manipulation ofthe boom and felling head combination for severing and collectingstanding trees.

I claim:

1. A method of felling trees and collecting the same, comprising:

a. placing a growing tree or trees in an accumulator for collecting suchtrees;

b. positively gripping said tree or trees placed in the accumulatorretaining the same therein;

0. severing said tree or trees, placed in the accumulator, from theirstump;

d. placing a further growing tree or trees in said accumulator inside-by-side relation and engagement with the previous trees collectedin the accumulator while maintaining said positive grip on thelatter-mentioned collected trees;

e. positively gripping said further tree or trees placed in theaccumulator retaining the same therein along with the previouslycollected trees; severing said further tree or trees from their stump;and

g. rcspcating the foregoing steps (a) to (e) until a selected quantityof trees has been collected in said accumulator.

2. A method as defined in claim 1 wherein said accumulator is attachedto a standing tree to be severed by forcibly driving the same onto thetree.

3. A method of felling trees which comprises:

a. placing a growing tree or trees in an accumulator for trees;

b. positively gripping said tree, holding the same firmly in said treeaccumulator;

c. severing said tree or trees placed in the tree accumulator; and

d. placing a further tree or trees in said tree accumulator andrepeating the step of severing the same until the tree accumulator hasbeen filled with the desired quantity of trees severed from their stump.

4. A device adapted to be secured to the free end of an extendible andretractable boom for severing trees in a growing position nd accumulatea plurality of the severed trees and firmly hold the same while usingthe device for severing further trees comprising in combination:

a. a frame having means on said frame arms thereon spaced apart from oneanother defining a selected area for receiving tree trunks, saidselected area being larger than the cross-sectional area of the stumpend of a plurality of trees and having a throat through which the treespass in placing the same in said area;

b. a gate movably mounted on said arms traversing said throatcontrolling movement of trees therethrough;

c. resilient means, on said frame, varying said area and biased to aminimum size area adjacent said gate; and

d. a tree severing device secured to said frame and located below thearms and gate in a tree cutting position, said severing device having acutting member movable relative thereto traversing at least the minimumsize of said area whereby trees to be severed must first be placed insaid accumulator and then severed.

5. A grapple as defined in claim 4 wherein said means varying the bitesize of the jaw and the gate together engage articles collected thereinat at least three positions, two of which are spaced relative to oneanother along the length of such articles on one side thereof and theremainder of which are on the opposite side whereby elongated articlesare stabilized in the accumulator.

6. Apparatus for severing a tree and accumulating a plurality of severedtrees comprising a vehicle, a boom mounted on said vehicle, a fellinghead pivotally mounted on said boom, means connected tosaid boom andsaid felling head for pivoting the latter relative to the boom between astanding tree severing position and a tilted, tree felled, position,said felling head comprising a tree accumulator grapple including aframe, means on said frame bounding an area larger than thecross-sectional area of the stump end portions of a plurality of treessevered from their stump and having a throat opening to theaforementioned bounded area through which the trees are moved sidewaysduring placing of the same in said area, a self-closing gate comprisingat least one member movably mounted on said frame traversing said throatpermitting trees to be forcibly moved therethrough into said area, meansmovably mounted on said frame for varying the size of said area andresiliently biased in a direction toward said throat providing a minimumsize of said area adjacent said throat and a tree severing devicemounted on said frame and located at a position below said grapple andgate in a tree severing position, said severing device having a cuttingmember movable to traverse at least said minimum bounded area forsevering a growing tree located therein, said accumulator grapplesuccessively receiving growing trees as they are placed therein andsubsequently severed from their respective stumps.

7. A tree accumulator grapple as defined in claim 4, wherein said gatecomprises a pair of cam members pivotally mounted on said frame means onsaid frame resiliently biasing said cam members to a gate-closedposition.

8. A tree accumulator grapple as defined in claim 7 wherein each of saidpivotally mounted cam members have an arcuate face engageable with treetrunks in the selected area.

9. A tree accumulator grapple as defined in claim 4 wherein; said meansresiliently biasing the gate to a closed position comprises anaccumulator, hydraulic piston cylinder assembly.

10. A tree accumulator grapple as defined in claim 7 wherein there are aplurality of cam-shaped members with such cam-shaped members beingmounted in pairs and including meanspivotally moving all of said cammembers in unison selectively to open said gate.

11. A grapple accumulator as defined in claim 4 wherein said frameincludes a longitudinally extending frame member and two or more pairsof arms secured to said frame member at positions spaced relative to oneanother longitudinally therealong, said pairs of arms being commonlyoriented relative to the frame and projecting outwardly therefrom withthe free terminal ends of the arms of the respective pairs being spacedfrom one another to provide said throat.

12. A tree grapple accumulator as defined in claim 4 wherein said meansvarying the area of the accumulator for receiving the trees comprises atleast one spring connected to said frame and at least one tree-engagingmember secured to said spring member.

13. A tree grapple accumulator as defined in claim 12, including two ormore springs, each anchored to said frame and wherein said tree-engagingmembers are secured to each of 'said springs.

14. A device adapted to be secured to the free end of an extendible andretractable boom for severing trees in a growing position and accumulatea plurality of the severed trees firmly holding such collected treeswhile using the device for severing further trees comprising incombination:

a. a frame including a longitudinally extending frame member;

b. two or more pairs of arms secured to said frame member at positionsspaced relative to one another longitudinally along said frame member,said pairs of arms being commonly oriented relative to the frame andprojecting outwardly therefrom with the free terminal ends of the armsof the respective pairs being spaced from one another partially boundinga selected area larger than the crosssectional area of the stump end ofa plurality of trees, the spaced-apart terminal ends of the armsproviding a throat through which trees pass while being placed in saidselected area;

c. a gate traversing said throat, controlling movement of treestherethrough, said gate comprising a pair of cam members pivotallymounted on the free end of respective ones of said pair of arms;

d. means on said frame varying said selected area;

e. means resiliently biasing said movable member to a selected minimumsize adjacent said throat; and

f. a tree severing device secured to said longitudinally extending frameadjacent one end thereof and having a cutting member movable in adirection perpendicular to the length of said longitudinally extendingmember traversing at least the minimum size of said selected areawhereby trees to be severed are first placed in the accumulator andsubsequently severed.

15. A device as defined in claim 14 wherein said spring meansresiliently biasing the movable member comprises a pair ofsemi-elliptical springs mounted on 1 said frame and having a portionthereof movable in a direction toward and away from said throat.

16. A device adapted to be secured to the free end of an extendible andretractable boom for severing and handling a plurality of trees,comprising in combination:

a. an accumulator for use in collecting trees and having open oppositeends through which trees in the accumulator may extend;

b. a gate movably mounted on the accumulator through which the treespass in being placed in said accumulator;

c. a tree severing device secured to the accumulator and located at aposition below a selected area in which trees collected in theaccumulator are located and oriented such as to allow severing standingtrees from their stump when located in the accumulator; and

d. tree engaging means movably mounted on the accumulator and arranged,together with said gate, to positively grip and firmly hold thecollected trees in the accumulator even while further trees areintroduced into the same.

17. A device as defined in claim 16 wherein said gate includes at leasttwo members pivotally secured to said accumulator at positions spacedapart from one another.

18. A device as defined in claim 17 including two pairs of pivotallymounted gate members with one pair spaced vertically above the other ina tree-cutting position.

19. A device as defined in claim 16 wherein said treeengaging means isresiliently biased in a'direction toward said gate.

20. A device as defined in claim 16 wherein said treeengaging means hasa roughened face directed toward trees in the accumulator for engagingthe same facilitating gripping thereof.

21. A device as defined in claim 20 wherein said roughened facecomprises a plurality of spikes.

22. A device as defined in claim 20 wherein said roughened surfacecomprises at least one rib extending transversely to the length of treesin the accumulator.

1. A method of felling trees and collecting the same, compriSing: a.placing a growing tree or trees in an accumulator for collecting suchtrees; b. positively gripping said tree or trees placed in theaccumulator retaining the same therein; c. severing said tree or trees,placed in the accumulator, from their stump; d. placing a furthergrowing tree or trees in said accumulator in side-by-side relation andengagement with the previous trees collected in the accumulator whilemaintaining said positive grip on the latter-mentioned collected trees;e. positively gripping said further tree or trees placed in theaccumulator retaining the same therein along with the previouslycollected trees; f. severing said further tree or trees from theirstump; and g. respeating the foregoing steps (a) to (e) until a selectedquantity of trees has been collected in said accumulator.
 2. A method asdefined in claim 1 wherein said accumulator is attached to a standingtree to be severed by forcibly driving the same onto the tree.
 3. Amethod of felling trees which comprises: a. placing a growing tree ortrees in an accumulator for trees; b. positively gripping said tree,holding the same firmly in said tree accumulator; c. severing said treeor trees placed in the tree accumulator; and d. placing a further treeor trees in said tree accumulator and repeating the step of severing thesame until the tree accumulator has been filled with the desiredquantity of trees severed from their stump.
 4. A device adapted to besecured to the free end of an extendible and retractable boom forsevering trees in a growing position nd accumulate a plurality of thesevered trees and firmly hold the same while using the device forsevering further trees comprising in combination: a. a frame havingmeans on said frame arms thereon spaced apart from one another defininga selected area for receiving tree trunks, said selected area beinglarger than the cross-sectional area of the stump end of a plurality oftrees and having a throat through which the trees pass in placing thesame in said area; b. a gate movably mounted on said arms traversingsaid throat controlling movement of trees therethrough; c. resilientmeans, on said frame, varying said area and biased to a minimum sizearea adjacent said gate; and d. a tree severing device secured to saidframe and located below the arms and gate in a tree cutting position,said severing device having a cutting member movable relative theretotraversing at least the minimum size of said area whereby trees to besevered must first be placed in said accumulator and then severed.
 5. Agrapple as defined in claim 4 wherein said means varying the bite sizeof the jaw and the gate together engage articles collected therein at atleast three positions, two of which are spaced relative to one anotheralong the length of such articles on one side thereof and the remainderof which are on the opposite side whereby elongated articles arestabilized in the accumulator.
 6. Apparatus for severing a tree andaccumulating a plurality of severed trees comprising a vehicle, a boommounted on said vehicle, a felling head pivotally mounted on said boom,means connected to said boom and said felling head for pivoting thelatter relative to the boom between a standing tree severing positionand a tilted, tree felled, position, said felling head comprising a treeaccumulator grapple including a frame, means on said frame bounding anarea larger than the cross-sectional area of the stump end portions of aplurality of trees severed from their stump and having a throat openingto the aforementioned bounded area through which the trees are movedsideways during placing of the same in said area, a self-closing gatecomprising at least one member movably mounted on said frame traversingsaid throat permitting trees to be forcibly moved therethrough into saidarea, means movably mounted on said frame for varying the size of saidarea and resiliently biased in a directIon toward said throat providinga minimum size of said area adjacent said throat and a tree severingdevice mounted on said frame and located at a position below saidgrapple and gate in a tree severing position, said severing devicehaving a cutting member movable to traverse at least said minimumbounded area for severing a growing tree located therein, saidaccumulator grapple successively receiving growing trees as they areplaced therein and subsequently severed from their respective stumps. 7.A tree accumulator grapple as defined in claim 4, wherein said gatecomprises a pair of cam members pivotally mounted on said frame means onsaid frame resiliently biasing said cam members to a gate-closedposition.
 8. A tree accumulator grapple as defined in claim 7 whereineach of said pivotally mounted cam members have an arcuate faceengageable with tree trunks in the selected area.
 9. A tree accumulatorgrapple as defined in claim 4 wherein said means resiliently biasing thegate to a closed position comprises an accumulator, hydraulic pistoncylinder assembly.
 10. A tree accumulator grapple as defined in claim 7wherein there are a plurality of cam-shaped members with such cam-shapedmembers being mounted in pairs and including means pivotally moving allof said cam members in unison selectively to open said gate.
 11. Agrapple accumulator as defined in claim 4 wherein said frame includes alongitudinally extending frame member and two or more pairs of armssecured to said frame member at positions spaced relative to one anotherlongitudinally therealong, said pairs of arms being commonly orientedrelative to the frame and projecting outwardly therefrom with the freeterminal ends of the arms of the respective pairs being spaced from oneanother to provide said throat.
 12. A tree grapple accumulator asdefined in claim 4 wherein said means varying the area of theaccumulator for receiving the trees comprises at least one springconnected to said frame and at least one tree-engaging member secured tosaid spring member.
 13. A tree grapple accumulator as defined in claim12, including two or more springs, each anchored to said frame andwherein said tree-engaging members are secured to each of said springs.14. A device adapted to be secured to the free end of an extendible andretractable boom for severing trees in a growing position and accumulatea plurality of the severed trees firmly holding such collected treeswhile using the device for severing further trees comprising incombination: a. a frame including a longitudinally extending framemember; b. two or more pairs of arms secured to said frame member atpositions spaced relative to one another longitudinally along said framemember, said pairs of arms being commonly oriented relative to the frameand projecting outwardly therefrom with the free terminal ends of thearms of the respective pairs being spaced from one another partiallybounding a selected area larger than the cross-sectional area of thestump end of a plurality of trees, the spaced-apart terminal ends of thearms providing a throat through which trees pass while being placed insaid selected area; c. a gate traversing said throat, controllingmovement of trees therethrough, said gate comprising a pair of cammembers pivotally mounted on the free end of respective ones of saidpair of arms; d. means on said frame varying said selected area; e.means resiliently biasing said movable member to a selected minimum sizeadjacent said throat; and f. a tree severing device secured to saidlongitudinally extending frame adjacent one end thereof and having acutting member movable in a direction perpendicular to the length ofsaid longitudinally extending member traversing at least the minimumsize of said selected area whereby trees to be severed are first placedin the accumulator and subsequently severed.
 15. A device as defined inclaim 14 wherein said spring means resiliently biasing the movabLemember comprises a pair of semi-elliptical springs mounted on said frameand having a portion thereof movable in a direction toward and away fromsaid throat.
 16. A device adapted to be secured to the free end of anextendible and retractable boom for severing and handling a plurality oftrees, comprising in combination: a. an accumulator for use incollecting trees and having open opposite ends through which trees inthe accumulator may extend; b. a gate movably mounted on the accumulatorthrough which the trees pass in being placed in said accumulator; c. atree severing device secured to the accumulator and located at aposition below a selected area in which trees collected in theaccumulator are located and oriented such as to allow severing standingtrees from their stump when located in the accumulator; and d. treeengaging means movably mounted on the accumulator and arranged, togetherwith said gate, to positively grip and firmly hold the collected treesin the accumulator even while further trees are introduced into thesame.
 17. A device as defined in claim 16 wherein said gate includes atleast two members pivotally secured to said accumulator at positionsspaced apart from one another.
 18. A device as defined in claim 17including two pairs of pivotally mounted gate members with one pairspaced vertically above the other in a tree-cutting position.
 19. Adevice as defined in claim 16 wherein said tree-engaging means isresiliently biased in a direction toward said gate.
 20. A device asdefined in claim 16 wherein said tree-engaging means has a roughenedface directed toward trees in the accumulator for engaging the samefacilitating gripping thereof.
 21. A device as defined in claim 20wherein said roughened face comprises a plurality of spikes.
 22. Adevice as defined in claim 20 wherein said roughened surface comprisesat least one rib extending transversely to the length of trees in theaccumulator.